Patient Case: A 45-year-old woman presents with a 6-month history of epigastric pain that worsens with meals and is relieved by antacids. She has a history of regular NSAID use for chronic back pain. Physical examination reveals mild epigastric tenderness. Endoscopy reveals an ulcer in the gastric antrum. Question: Which test is most appropriate to confirm the presence of H. pylori in this patient?
